The Collaborative International Dictionary of English v.0.48:

Yuck \Yuck\, v. i. [Cf. G. jucken, D. yeuken, joken. See
   Itch.]
   To itch. [Prov. Eng.] --Grose.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Yuck \Yuck\, v. t.
   To scratch. [Prov. Eng.] --Wright.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

yuck \yuck\, interj.
   an interjection expressing repugnance or distaste.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

yuck \yuck\ n.
   a laugh; also, a joke or gag; -- usually used in the plural,
   as, the skit got lots of yucks. [slang]

   Syn: laugh; gag; joke
        [PJC]

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "yuck":
   belly laugh, boff, boffola, burst of laughter, cachinnation,
   cackle, chortle, chuckle, convulsion, crow, fit of laughter,
   gales of laughter, giggle, guffaw, ha-ha, hearty laugh, hee-haw,
   hee-hee, hilarity, ho-ho, horselaugh, laugh, laughing, laughter,
   outburst of laughter, peal of laughter, risibility,
   roar of laughter, shout, shout of laughter, shriek, snicker,
   snigger, snort, tee-hee, titter, yuk-yuk